


Honk, Honk

by fuzipenguin



Category: Transformers Generation One
Genre: Alt-Mode Sexual Interfacing, Awkward Sexual Situations, Established Relationship, M/M, Other, Plot What Plot/Porn Without Plot, Sexual Humor, Twincest
Language: English
Status: Completed
Published: 2015-10-12
Updated: 2016-10-05
Packaged: 2018-04-26 01:25:52
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,500
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4984501
Author URL: https://archiveofourown.org/users/fuzipenguin/pseuds/fuzipenguin
Summary: <blockquote class="userstuff">
              <p>Sunstreaker really needs to learn how to say 'no' to his twin...</p>
            </blockquote>





	1. Chapter 1

     “Are you sure this is going to work?” Sunstreaker asked nervously, slowly backing up. He braked just moments before his bumper touched Sideswipe’s shins.

     “Pretty sure,” Sideswipe replied, stroking the underside of Sunstreaker’s spoiler. “Why? Don’t you trust me?”

     His brother continued to pet Sunstreaker, pinching the supports of his spoiler and then tickling his taillights. Despite his apprehension, Sideswipe’s touch was familiar, his energy field surrounding him with confidence and eagerness. Sunstreaker’s own field was already tentatively unfurling, meshing with Sideswipe’s.

     “I trust you. But you were doing… hngh… math.”

     Sunstreaker shuddered when Sideswipe’s fingers slipped into the crack of a transformation seam on the underside of Sunstreaker’s bumper. The warm digits caressed the sensitive edges of the seam, and Sunstreaker’s plating marginally loosened. Enough for Sideswipe to slip his fingers between the edges and stroke several wires lying close to the surface.

     Sideswipe abruptly tugged on those wires, sending a bolt of pleasure-pain through Sunstreaker. His tires squeaked on the decking as they restlessly shifted back and forth.

     “Hey, I’m good at math!” Sideswipe protested. “How do you think I ruled the markets back home? Now _physics_ … physics I may not be so good at.”

     “Oh, that makes me feel better,” Sunstreaker replied drily. Then he startled when Sideswipe leaned forward and mouthed at the edge of Sunstreaker’s spoiler. If he’d been in root mode, he would have clenched his fists and offlined his optics to enjoy the sensation. As it was, he nudged closer to his brother’s legs, engine idling higher.

     They always transformed together so they had never before explored each other’s alt forms with the intent to stimulate. It was like discovering his hot spots all over again. His spoiler was not this sensitive in root form, but Sideswipe’s attentions to the area now were really revving Sunstreaker up. He supposed it made sense; once he transformed into his vehicle form, the spoiler’s dermal sensitivity automatically increased to better measure air drag.

     “Keep doing that,” Sunstreaker choked out, his plating rippling in response to the sensations Sideswipe’s lips and denta were producing.

     “K,” Sideswipe mumbled, enthusiastic lust surging in his field.

     Sideswipe continued to touch and kiss Sunstreaker’s entire rear half, making delighted sounds every time he found another area which produced a twitch or moan. It didn’t take long for Sunstreaker’s charge to flare up; the embers of arousal had already been ignited during their groping of one another prior to Sunstreaker’s transformation. Sideswipe had encouraged some lengthy foreplay, wanting to warm them up and ease nerves.

     Sunstreaker’s nerves, that is. And Sideswipe really had no need of warming up. He had been raring to go since they had gotten off shift. Even now, Sideswipe’s energy field swirled around him, pulsing steadily with excitement.

     “You about ready?” Sideswipe asked, digging his fingers into Sunstreaker’s rear wheel wells for the first time.

     Sunstreaker arched into the touch, managing a wobbly, “go for it.” Why were his _wheel wells_ sensitive?!

     “Sweet,” Sideswipe murmured. “K, hold on.”

     With that useless warning – he didn’t have hands at the moment, how was he supposed to hold on? – Sideswipe got a good grip on the underside of Sunstreaker’s bumper and hefted him up and back onto Sideswipe’s lap. Sunstreaker’s front tires squealed a protest as he was drug across the floor, and he hurriedly unlocked his brakes.

     The sudden lack of resistance overbalanced Sideswipe, and he fell backwards, Sunstreaker’s rear end crashing down on top of him. Sunstreaker froze, only his front tires touching the ground and fighting the urge to transform back to his root mode. He felt precariously balanced, and he didn’t like it one bit.

     “Ow,” Sideswipe muttered from behind him. “OK, next time, you disengage your brakes first before I pull, yeah?”

     “Next time? I’m not so sure about _this_ time,” Sunstreaker replied, his back tires edgily spinning in midair on either side of Sideswipe’s hips.

     “Slight miscalculation,” Sideswipe chirped, cheeriness making a full return. “Right, let me just…”

     Sideswipe readjusted his grip and with a fair amount of wriggling and shifting around, finally propped Sunstreaker’s tires on Sideswipe’s spread thighs. The position felt unnatural, and Sunstreaker could feel himself tensing back up all over again.

     “I’m not gonna let you fall,” Sideswipe said reassuringly, caressing Sunstreaker’s bumper. “And I gotta tell you, your aft looks great like this.”

     Well, of course it did. He looked good at any angle.

     “You _better_ not let me fall,” Sunstreaker grumbled, a little mollified. “I might get a scratch.”

     “Primus forbid. Now open up.”

     Sideswipe’s hands reached up under Sunstreaker’s bumper and patted at his undercarriage, blindly stroking the edges of more transformation seams. He reached the general area of where Sunstreaker’s pelvis would be, face ending up smushed against one of Sunstreaker’s taillights as he strained to reach.

     Awkward. This entire thing was awkward. Sunstreaker had known it would be, no matter how much Sideswipe had planned things out. But it was Sideswipe, and Sunstreaker still hadn’t learned to say no to him after all these years together.

     “Come on, Sunny. Help me out a little here,” Sideswipe muttered before nipping at Sunstreaker’s left spoiler support.

     Ex-venting a sigh, Sunstreaker sent the command to retract his interface cover. He had to override several failsafes as well as perform a tricky microtransformation sequence to make it actually happen. Interface equipment was not meant to be barred while in his form. Go figure.

     “Ah ha!” Sideswipe exclaimed triumphantly, following the sound of reconfiguration. His fingers probed around Sunstreaker’s now open array, exploring the edges. “Yeah, good idea. Keep your spike retracted. Hate to see it broken off if you slipped.”

     Sunstreaker’s plating clamped down at the thought. “I can’t believe you talked me into this,” he muttered in despair.

     Sideswipe ignored him, instead slipping a finger into Sunstreaker’s valve. The angle was a little off, so Sideswipe couldn’t do more than pump shallowly. Nevertheless, the touch still felt good, and Sunstreaker’s tension eased a fraction. He was well lubricated from their earlier play and easily took two more of Sideswipe’s fingers when they slid inside.

     “How’s it feel?” Sideswipe asked, field pressing close in aroused curiosity.

     Good question. The sensation of stimulation was the same, but it was disconcerting feeling it in alt form. He couldn’t express pleasure the way he normally would; this more rigid form prohibited him from undulating against Sideswipe’s fingers or using hands to direct him where Sunstreaker wanted him.

     He mainly felt very exposed and almost helpless. If the trust between them wasn’t so deep, Sunstreaker would have called the whole thing off. But he knew Sideswipe would take care of him and even stop if Sunstreaker asked for it. Oh, Sideswipe would whine the whole time, but he would ease Sunstreaker back to the floor and it would be the end of things.

     So Sunstreaker struggled to find a way to express all that and ended up with, “fine.”

     Sideswipe snorted in disbelief, patting Sunstreaker’s right rear tire. “Uh huh. Well, at least you’re wet.”

     And he was at that, and getting wetter. Despite Sideswipe not being able to thrust his fingers very deeply, the odd angle made his brother’s digits rub distractingly against a string of oft ignored nodes lining the far rim of his valve. Pleasure was starting to collect in a warm pool within his belly.

     Or where his belly normally would be. More like the area around his front seats. But still. Nice.

     Sideswipe fingered him for a few minutes more until lubricant dripped freely from Sunstreaker’s port and he had to initiate a lock on his joints. He wanted to _move_ , push back onto Sideswipe’s clever digits, but that translated into bouncing on his tires. And as he was so carefully perched on Sideswipe’s legs, Sunstreaker feared he would slip off to one side or another.

     “All right, I think it’s time for phase 3,” Sideswipe announced after Sunstreaker began producing a frustrated whine he just couldn’t seem to hold back. “You good to go?”

     “Just do it,” Sunstreaker commanded, taillights flashing in an irritated pulse.

     “Yes, Master,” Sideswipe snarked, removing his fingers from Sunstreaker’s valve. Cue another whine, this one disappointed. “All right, I’m gonna move you again, so just… let me, ok?”

     Sunstreaker made a noncommittal sound, suddenly nervous again. Sideswipe retreated from his awkward position beneath Sunstreaker and gripped him firmly once more. Fighting down the urge to engage his breaks, Sunstreaker allowed himself to be mech-handled. 

     Sideswipe slowly leaned backwards in his adjustable chair until he was reclining at a twenty-five degree angle. As he moved, he drew Sunstreaker’s rear end further into his lap and then onto his chest, bracketing Sunstreaker’s frame between Sideswipe’s thighs. Sunstreaker’s back bumper ended up on level with his brother’s shoulders, his front bumper a hair’s breadth away from the floor. Front tires firmly placed on the ground and with the majority of his body lying across his brother’s chest and abdomen, Sunstreaker felt a little more secure. Unfortunately, this wasn’t the final position.

     “I got you, Sunny, it’s ok,” Sideswipe murmured in reassurance, planting his feet more firmly on either side of Sunstreaker’s front tires. With a grunt, Sideswipe gripped Sunstreaker’s frame just in front of his rear tires and lifted him several inches up into the air. The nose of his alt mode ended up resting lightly against the decking.

     “All right. _Now_ lock your breaks,” Sideswipe instructed.

     “Are you _sure_ this is going to work?” Sunstreaker questioned once more, doing as his brother commanded.

     “Don’t know until we try, right?” Sideswipe replied cheerfully.

     Suddenly something scraped against Sunstreaker’s undercarriage, and he twitched in surprise. “Are you…”

     “Yup. Ok, now here’s something I didn’t plan on. Damn, I wish you had your hands right now,” Sideswipe complained, little plinking sounds echoing from beneath Sunstreaker’s ventrum as Sideswipe tried and failed to aim his spike towards Sunstreaker’s valve.

     After about a minute of Sideswipe’s fumbling, Sunstreaker began directing him. “To the left. No, your _other_ left, you idiot. You overshot, go back… not that far! I said to the left!!”

     Suddenly, the blunt head of a spike was rubbing against Sunstreaker’s folds. It caught on the rim of his valve before Sideswipe shifted again, angling his hips up and bringing Sunstreaker’s tail end down a fraction. And then they were lined up perfectly, and Sideswipe thrust in deep, his triumphant hum spiraling down into a groan.

     “See? Told you it would work,” Sideswipe boasted, voice a little strained.

     “Uh huh,” Sunstreaker replied absently, still trying to process everything. It was so _odd_ … his port felt incredibly full. It probably had something to do with the way his interface array was arranged in this form; he’d taken Sideswipe’s spike thousands of times before and it had never felt this big.  

     “Primus,” Sideswipe gasped after easing out and tentatively pushing back in. “You’re so tight. Are you ok?”

     “Nnghh,” Sunstreaker replied in a moan. It didn’t hurt per se, but it certainly tested the limits of his valve in all kinds of delicious ways. “Go… go slow…”

     “K,” Sideswipe agreed, gently sliding out before carefully thrusting up into Sunstreaker again. “If you want me to stop…”

     “ _Don’t stop_ ,” Sunstreaker growled. He was committed at this point. And it certainly was pleasurable despite the weird position.

     “Aye, aye!”

     Sideswipe proceeded to frag him with long, deep strokes, his pelvis brushing against Sunstreaker’s undercarriage with soft little chirrs of sound. Sunstreaker gradually relaxed into Sideswipe’s strong grip when it became apparent that he wasn’t about to be dropped. With one less thing to worry about, Sunstreaker finally gave himself over to sensation.

     And _oh_ , what sensation it was. Despite the large amount of lubricant he was producing, he still remained tight, his port compressed by his other internal workings. Because of the snug fit, _every_ node in his valve was stimulated with each new glide of Sideswipe’s spike. Charge gathered rapidly in Sunstreaker’s lines, snaps of electricity sparking out from under his armor to whip against his brother’s.

     “Best. Idea. _Ever_ ,” Sideswipe panted, pace beginning to pick up a little. “I get to frag you _and_ stare at your aft the entire time. This is… _awesome!_ ”

     Sunstreaker groaned, half in arousal, half in irritation. Despite holding Sunstreaker up and essentially doing all the work, Sideswipe _still_ found the energy to gab.

     “You close, baby?” Sideswipe continued, sinking deep and circling his spike within the depths of Sunstreaker’s port.

     Sunstreaker’s only answer was a thin moan, too focused on the sensation of Sideswipe’s spike head grinding against Sunstreaker’s ceiling node. He really wanted to cant his hips downwards, take his brother’s spike even deeper. But he didn’t have hips like this, and he was completely reliant on his twin.

     He could do nothing but remain quiescent in Sideswipe’s grasp, helpless to whatever pleasure his brother chose to give him.

     Fortunately, Sideswipe was a giving mech.

     “Oh, yeah… you’re close,” Sideswipe murmured, with a smug swell of his energy field. Before Sunstreaker could growl at him, Sideswipe withdrew almost completely before plunging deep again. Once full seated, he let Sunstreaker’s weight drop a little so his ceiling node was snugly pressed against Sideswipe’s spike tip. He circled his hips in a full 360 degree rotation, grinding against the sensor and lighting up Sunstreaker’s neural net.

     He moaned unashamedly, twitching in Sideswipe’s hands, and aching for more. “Sides, please!”

     “I’ll get you there, bro,” Sideswipe said, harsh ventilations nearly obscuring the words. “Just hold still.”

     Easier said than done. Sideswipe continued the pattern of a deep thrust followed by that circular grinding, and it was driving Sunstreaker up the wall. His arousal just kept ratcheting higher and higher, charge swelling within him until he thought he would burst at the seams.

     Sideswipe began thrusting harder, Sunstreaker nearly bouncing from the force, and that wave of pleasure abruptly crested and washed over him. Sunstreaker cried out, practically vibrating as overload gripped him tight and sent a sweet fire through his internals. Over the rushing in his audials, he heard a car horn blare and Sideswipe cursing in a strained voice.

     “Primus, Sunny! _Frag_ , that’s good,” Sideswipe groaned, pulling Sunstreaker down until their pelvic areas were flush. Sideswipe’s hips hunched upwards, trying to get as deep as possible as overload was forced out of him by Sunstreaker’s rippling valve. Transfluid burst from Sideswipe’s spike, Sunstreaker’s sensor nodes tingling as they were compressed from the extra pressure. It was more than enough to send Sunstreaker into another overload, just as he was coming down from the first.

     He felt a bit like he was flying. His gyros spun, confused from an overload experienced in this mode and position. Sideswipe’s grip remained firm however, clenching even tighter in his climax. Sunstreaker relished the slight pain of plating buckling beneath Sideswipe’s fingers; it was the only thing grounding him.  

     “Frag, that was so _hot_ ,” Sideswipe panted, rigid beneath him. As Sunstreaker’s port spasms finally calmed, Sideswipe’s pelvis gradually sank down, spike slipping free. He dropped down completely onto the chair, tightening his knees around Sunstreaker’s frame and giving him an extra measure of stability.

     Sideswipe then let Sunstreaker’s rear end sag, his entire weight gradually coming to lie atop Sideswipe’s chest and belly. Sunstreaker gratefully rested there, feeling too drained to transform or roll forward and plant all four tires on the floor.

     Arms curled around Sunstreaker’s rear fenders, pulling him close to Sideswipe’s chest. “Are you cuddling me?” Sunstreaker queried, a little amused at the thought. He bet the two of them looked a little ridiculous right now. But there was no one else there to see, so who cared? After a good overload, Sunstreaker certainly didn’t.

     “Mmm hmm,” Sideswipe replied, squeezing Sunstreaker with a little happy wiggle. “We need to do that again sometime. I want a turn.”

     Sunstreaker gave a little fond sigh. “Of course you do.”

     They were silent for a minute, just enjoying the post overload lassitude when Sideswipe started snickering out of the blue.

     “You know what’s kinda adorable? In your alt mode, you honk your horn when you come.”

 

~ End


	2. Just Rewards

**Summary for the Chapter:**

> What follows after Alt mode sex?

**Notes for the Chapter:**

> nyaaanswipe asked: Drabble extension for "Honk, Honk"... it's too adorable, maybe some extra fluff at the end?

     After several minutes, Sideswipe jostled Sunstreaker out of a light dose. “You gonna transform back?”

     “Mmm. I’m actually pretty comfortable here,” Sunstreaker replied truthfully. 

     “Well, I aint. Transform back. I want proper cuddles,” Sideswipe commanded, jostling him again. 

     Stifling a sigh, Sunstreaker initiated his transformation sequence. Sideswipe’s voice had held a familiar note of petulance. It was a clear warning that he would keep on pestering until he got his way. Not that Sunstreaker could really complain; snuggles in their bed would ultimately be more comfortable if one of them remained in alt form.

     Sunstreaker flipped neatly to his feet at the end of his sequence, stretching his arms up behind his back until his spinal strut gave a satisfying ‘pop’. He winced a little at the twinge his valve sent him. No outright pain, but definitely tender. 

     “Doing ok?” Sideswipe asked, surging to his feet with a look of concern.

     “A little sore, nothing too bad. But you’re not spiking me for at least a day,” Sunstreaker informed him.

     “No problem,” Sideswipe conceded easily, with one last look at Sunstreaker’s groin. “I got other plans anyway.”

     “Oh, lovely,” Sunstreaker sighed with a roll of the optics. Sideswipe was always planning something, whether it be a new prank or the next great interfacing adventure. “Well, let’s get to the berth then. I’m not cuddling you on the… hey!”

     Sunstreaker yelped as he was taken hold of by the shoulders, turned, and shoved unceremoniously down onto the reclined chair. Still wobbly from his overload, Sideswipe mechhandled him with almost embarrassing ease.

     “What are you doing, you glitch?!” Sunstreaker demanded, looking up at his twin from flat on his back. “I thought you wanted cuddles?”

     “Mmm, I do. But later. I told you – I have plans. And part of those plans is giving you a reward,” Sideswipe purred, dropping to his knees between Sunstreaker’s spread thighs. Sunstreaker craned his head up to watch his brother bend and nuzzle Sunstreaker’s still open interface panel. 

     The sight of Sideswipe between Sunstreaker’s legs never failed to make his fuel pump skip a beat. He licked his lips, transfixed by the smear of lubricant that had transferred itself to Sideswipe’s cheek. 

     “Reward for what?”

     “You went along with my idea. I know it was weird for you,” Sideswipe explained, nosing at Sunstreaker’s spike housing. In response, it spiraled open, pressurizing length eagerly emerging. 

     “Yeah, it was,” Sunstreaker admitted. “But I thought overload was the… re… reward.” Sunstreaker trailed off, optics going out of focus as Sideswipe licked the head of Sunstreaker’s spike. Warm fingers wrapped around the base and squeezed, and Sunstreaker let his head slowly fall backwards. It left him staring at the ceiling instead of his twin’s devious smile, which was a pity. But his neck cables were suddenly too weak to support his helm. 

     “Nope. Your reward is yet to come, bro.”

 


	3. Turnabout's Fair Play

**Notes for the Chapter:**

> nyaaanswipe asked: A sequel to Honk, Honk. Positions reversed. C:

     Unlike Sunstreaker, Sideswipe had no qualms about being on his back in alt mode.

     With a little help from this twin, he had been flipped onto the roof of his Lamborghini form, valve tingling the entire way in anticipation of receiving his brother’s spike. He had already been fingered quite thoroughly, in much the same way as he had done for Sunstreaker when it had been him in vehicle mode. So Sideswipe was practically dripping and more than ready. 

     Which was why when seconds without being touched turned into a minute, Sideswipe spun his tires in irritation, switching to his tertiary visual sensors to see what was taking so long. His brother was standing off to the side, staring down at him with a thoughtful look on his face. 

     “What’s the hold up, bro?” Sideswipe asked impatiently. He wanted to wiggle enticingly, but that translated into nothing more than a flick of his wiper blades. 

     “How’s this going to work exactly?” Sunstreaker replied doubtfully, gesturing at Sideswipe. “You’re going to be teetering all over the place.”

     Sideswipe took stock of the situation. He _was_ precariously balanced, especially when one considered how small the roof circumference was above his seating area. 

     A shrug translated into an odd flexing of his tires away from his frame. “I dunno. Didn’t you plan this?”

     Sunstreaker’s arms dropped to his hips and he glared defensively at Sideswipe. “You’re the planner! You mean you didn’t do your physics thing? I tell you right now, you’re not getting in my lap like I did with you. You ended up with way too many scratches!”

     As his brother continued to rant, Sideswipe idly spun his tires, his charge only continuing to grow. His twin could be a real aft sometimes, but this particular type of outburst was just meant to cover up uncertainty. It was one of his brother’s more cute quirks, and Sideswipe left him to it as he began calculating the safest way for both of them to overload spectacularly.

               

**Author's Note:**

> Wanted to see some alt mode sex. So I did it. Lots of research went into this. I had to stare at porn images and fiddle with my Sunny and Sides figures. So... you know... not a bad time all around ;)


End file.
